Stendhal said of one of his most significant works, De l'amour, published in 1822, that it was ‘ideological’. ‘Ideology’ in a pre-Marxist sense, the meaning used by Comte Destutt de Tracy, a contemporary of Napoleon, to whom we owe the term's invention, is a science. Emerging from the language developed by the empiricists, particularly the British ones, ideology as a discipline has the task of describing ideas, their components and especially their origins, its aim being to understand how ideas emerge and evolve. But instead of trying to study how an idea develops, Stendhal admitted that he was more interested in a particular feeling. And he embarks on a description of love, particularly from the second chapter on, with the clear aim of reaching an understanding of the emotion's components. In fact he will concern himself only with ‘passionate love’, amour passion. And this is important for several reasons that I shall explain, the context of the period being one of the most salient. At that time love was turning towards ‘passionate love’, that is, the passion par excellence. For the idea of love that had prevailed prior to the 19th century was not associated with passionate love. It is true that Stendhal had not failed to quote the Lettres de la religieuse portugaise (a 17th-century work, attributed to Mariana Alcoforado, a Portuguese nun, but which, as we now know, is part of French literature), nor other texts earlier than the 17th and 18th centuries that evoked a type of emotion as strong as passionate love. But, as the 18th turned into the 19th century, passionate love was, generally speaking, a novelty and Stendhal is among those who were to elaborate most extensively on this theme.